The Universal Mobile Telecommunication Service (UMTS) standard provides a compatibility standard for cellular mobile telecommunications systems. The UMTS standard ensures that user equipment (UEs) operating in a UMTS system can obtain communication services when operating in a system manufactured according to the standard. To ensure compatibility, radio system parameters and data transfer procedures are specified by the standard, including protocols governing digital control messages and bearer traffic that are exchanged over an air interface.
The UMTS standards provide, in 3GPP TS 25.344 (Third Generation Partnership Project Technical Specification 25.344), 3GPP TS 23.246, and 3GPP TS 23.846, for a provision of a Multimedia Broadcast/Multicast Service (MBMS) service by a UMTS communication system to UEs serviced by the system and subscribed to the service. More particularly, the UTMS MBMS standards provide for delivery of MBMS data to subscribed UEs through well-known unicasting or multicasting techniques in the cellular domain. However, increased radio and network efficiency is critical to an eventual widespread adoption of MBMS by service providers. In order to improve the efficiency of MBMS service delivery, it has been proposed that a High Speed Downlink Packet Access (HSDPA) high order modulation/demodulation scheme be implemented in cellular Node Bs and UEs respectively. Thus each cellular Node B would have the ability to provide both low rate and high rate MBMS data services. But implementation of HSDPA imposes power allocation problems on the Node Bs. In particular, studies have shown that under certain traffic and service constraints, HSDPA will consume a significant percentage of the transmit power of a cellular Node B and severely limit an amount of power that may be allocated to dedicated channels by the Node B, thereby imposing severe capacity constraints upon the Node B and a communication system as a whole.
Therefore, a need exists for a method and apparatus that provides for high rate MBMS data services without imposing the system capacity constraints resulting from the employment of HSDPA by a cellular Node B.